This invention relates, in general, to a method for growing epitaxial films, and more particularly to a method for growing high quality epitaxial films using low pressure metalorganic chemical vapor deposition (MOCVD).
The quality of epitaxial film surface morphology is extremely important in high performance electronic and optoelectronic III-V and II-VI compound devices. Film smoothness influences the quality of submicron lithography and a rough surface morphology at heterointerfaces may degrade electron mobility. Smooth epitaxial film morphology also plays an important role in the operation of optoelectronic devices in such areas as the interfacial recombination velocity, scattering from optical waveguides and the line width of emission from quantum wells.
Epitaxial film morphology is dependent upon various growth parameters such as substrate temperature, substrate orientation, ambient pressure and reagent mole fraction. The growth of epitaxial films on substrates that are critically misoriented from a singular plane is well known in the art. Misorientation effects have been previously observed in liquid phase epitaxy (LPE), chloride-transport vapor phase epitaxy (VPE) and molecular beam epitaxy (MBE). Most recently, atmospheric pressure MOCVD has been used to grow epitaxial films on critically misoriented substrates. The above methods of growing epitaxial films on misoriented substrates have lead those skilled in the art to believe that high quality epitaxial films may be grown on substrates having small (less than 3.0 degrees) misorientations from a singular plane. However, it has been shown by low pressure MOCVD that the growth of epitaxial films on substrates being slightly misoriented from the origin of a singular plane will provide rough, faceted epitaxial films due to long range reordering which lowers step surface energy near a singular plane. Therefore, to build high quality electronic and optoelectronic devices, it is critical that a method of growing high quality epitaxial films be provided.